1. Field of the Invention
The present invention relates to a data storage device for recording data on a memory medium, such as a magneto-optical disk, and in particular to a data storage device which ensures the secrecy and the security of recorded data.
2. Related Arts
Generally, a data writable memory medium (hereinafter referred to as a medium), such as a magneto-optical disk (MO), can be inserted into or removed from a data storage device (hereinafter simply referred to as a storage device) which reads and writes predetermined data from and to the medium. When a medium is loaded into the storage device, operational control for the storage device is provided by commands issued by a superior apparatus, such as a personal computer connected to the storage device by a SCSI cable.
Conventionally, by taking compatibility into account, reading data from and writing data to a medium can also be performed by a storage device other than the device which was originally employed for writing data.
FIG. 19 is a flowchart for data reading/writing processing performed by a conventional storage device. After a medium is inserted into the storage device at step Si, at step S2 a process for loading the medium is started. That is, the medium is positioned at a predetermined location within the storage device and is rotated at a controlled revolution rate, and a process is performed to set the medium to a data reading enabled state or to a data writing enabled state. At step S3, medium information, such as configuration and memory capacity of the medium, are read, and at step S4 the reading and writing of data is enabled by the employment of an operation or a processing procedure based on the information.
Therefore, a problem has arisen in that once a memory medium has been acquired, secret data recorded on the memory medium, such as the contents of a client database or design data, can easily be stolen or altered.
It is, therefore, one objective of the present invention to provide a data storage device that ensures the secrecy and the security of data recorded on a memory medium.
To achieve the above objective, according to the present invention, a data storage device which reads data from and/or writes data to a memory medium, comprises:
an acquisition unit for acquiring management information which is recorded by a predetermined form in said memory,
a controller for converting said management information into an another form.
The controller rearranges the management information to convert the management information into another form; the controller shifts the management information by at least one bit to convert the management information into another form; or the controller encodes the management information to convert the management information into another form.
Further, the controller restores the converted management information to the predetermined form according to a relationship between a first identifier recorded on the memory medium and a second identifier recorded in the data storage device.
When, for example, the two identifiers match, the acquisition unit can acquire the management information, and the reading and writing of data is enabled. When the two identifiers do not match, restoration of the management information to a predetermined form is not effected, so that the acquisition unit can not acquire the management information and the reading and writing of data is disabled.
To achieve the above objective, according to the another present invention, a data storage device which reads data from and/or writes data to a memory medium, comprises:
an acquisition unit for acquiring management information which is recorded on a predetermined area of said memory medium,
a controller for moving said management information to another area.
The acquisition unit acquires the moved management information from the another area according to a relationship between a first identifier recorded on the memory medium and a second identifier recorded in the data storage device.
For example,each the first and the second identifiers is a serial number for the data storage device and the predetermined area is a disk definition sector (DDS) area of the memory medium.
When, for example, the two identifiers match, the management information can be acquired from the another area, and the reading and writing of data is enabled. When the two identifiers do not match, and the acquisition unit does not acquire the management information because the acquisition unit tries to acquire the management information from the predetermined area where management information is not present, and the reading and the writing of data are disabled.
On the memory medium is recorded read address information or write address information, which is used to control data reading or writing respectively. When the first and the second identifiers match, the controller may permit or inhibit the reading of data in accordance with the read address information or may permit or inhibit the writing of data in accordance with the write address information.
Preferably, provided for the memory medium is a first password. For example, when the reading of data is inhibited in accordance with read address information, if the first password matches a second password sent from a controller of the data storage device, the controller permits the reading of data.
The memory medium includes address information which designates at least one of a plurality of data sets which are recorded on the memory medium. For example, the controller may permit or inhibit the reading of data corresponding to the address information when both the first and the second identifiers match.